<form action="{$url}" method="post" class="ms-md-3">
    {assign var=aSizes value=array(10, 20, 50, 100, 200, 500)}
	<select class="form-control select" onchange="this.form.submit()" name="limit" data-width="160" data-container-css-class="select-sm">
		{foreach from=$aSizes item=size}
			<option value="{$size}" {if !empty($limit) && $limit eq $size}selected{/if}>Показать по: {$size}</option>
		{/foreach}
	</select>
</form>